1. Field of the Invention:
This invention relates to a method and an apparatus for building a pipeline and a shield tunnelling machine used for building the pipeline and, more particularly, to a method for building a new pipeline while breaking a plurality of pipelines built in the ground and extending parallel to each other to lay the new pipeline in place of the broken pipeline; and to an apparatus for embodying this method and an excavating machine used for building the pipeline.
2. Description of the Prior Art:
In one of methods for building a new pipeline having a diameter larger than those of a plurality of existing pipelines such as sewer pipes, power line pipes, telephone line pipes, or the like while breaking the existing pipelines, there has been generally employed a method of construction which comprises the steps of excavating a ditch in a spot where the existing pipes to be renewed are disposed, extending the ditch to expose and remove the pipes, disposing a new pipe in place of the existing pipes and thereafter refilling the ditch. According to this method of construction, it is necessary to excavate the ditch. Therefore, this method is limited to locations where such excavations are possible.
In order to overcome the above problem, it is possible to renew a plurality of existing pipelines into a new pipeline by utilizing a pipe propelling method. However, according to the conventional pipe propelling method, a shield body is rotated by a reaction of rotation of a cutter assembly, and the cutter assembly has to be rotated clockwise and counter clockwise. Further, the troublesome operation of controlling the advancing direction of the machine has to be done in order to advance the excavating machine along a predesigned route.